This invention relates to an auxiliary equipment arrangement in an engine and more particularly to an improved drive arrangement for driving engine auxiliaries from an intermediate shaft of the engine.
There has been proposed a type of engine that has an intermediate shaft which is driven off a location between the ends of the main crankshaft and which itself drives a plurality of accessories. Such an arrangement is shown in Japanese Published Application 2000-205066, published Jul. 25, 2000.
With this arrangement, a plurality of accessories is disposed around a pulley at one end of the intermediate shaft of the engine. These accessories all are driven by a single serpentine flexible transmitter. As a result of this arrangement, the bearings on the intermediate shaft are loaded primarily on only one side of the rotational axis of the shaft causing high loadings on its bearings, particularly those adjacent the driving pulley. In addition, it is necessary to place idlers or further accessories close together on the opposite side of the engine in order to maintain a substantial contact of the flexible transmitter with its driving pulley. This results in not only high bearing loads, but also in increased weight and size of the engine in order to accommodate their loads. In addition, this driving arrangement is disposed outwardly of one end of the engine and thus, adds to the overall length of the engine.
It is, therefore, a principal object to this invention to provide an improved accessory drive for driving engine accessories from an intermediate shaft of the engine.
In addition to those external accessories for the engine, there are also a number of internal accessories that are driven from the engine. An examples of such internal accessories is the oil pump, which collects oil from the oil tank or crankcase and circulates it to the various components of the engine for their lubrication. Frequently, this oil pump is located in the crankcase and is driven from the engine crankshaft. One problem with this type of location is that the engine oil pump is very difficult to obtain for servicing and frequently even the engine must be removed from the chassis of the vehicle to service the oil pump.
It is, therefore, a further object of this invention to provide an improved oil pump drive for an engine wherein the engine oil pump can be easily removed for servicing.
It is a further object to this invention to provide an improved arrangement for driving the oil pump directly from an end of the intermediate shaft.
This invention is adapted to be embodied in an internal combustion engine having a cylinder block with a plurality of aligned cylinder bores, each of which contains a piston for driving a crankshaft journal led in a crankcase formed at the lower end of the cylinder block. An auxiliary shaft is journal led for rotation about an auxiliary shaft axis at one side of the cylinder block and is driven by the crankshaft. A pair of pulleys is fixed at one end of the auxiliary shaft. A pair of engine accessories is mounted at the one side of the cylinder block on diametrically spaced sides of the auxiliary shaft axis. First and second flexible transmitters drive the pair of engine accessories from respective ones of the pair of pulleys.
In accordance with another feature of the invention, the crankshaft is journal led by at least two bearings positioned in opposite end walls of the engine and at least one of the auxiliary shaft pulleys is disposed inwardly of at least one of the engine end walls so as to reduce the overall length of the engine.
Another feature of the invention is adapted to be embodied in an internal combustion engine having a cylinder block with a plurality of aligned cylinder bores each containing a piston driving a crankshaft journal led in a crankcase formed at a lower end of the cylinder block. An auxiliary shaft is journal led for rotation about an auxiliary shaft axis at one side of the cylinder block and is driven by the crankshaft. An engine accessory is driven by the auxiliary shaft externally of a body of the engine. An oil pump is driven from the end of the auxiliary shaft adjacent the external engine accessory.